WASHINGTON -- Janina Riley noticed a woman muttering behind her in the checkout line as she paid for food at a Giant Eagle grocery store in Pittsburgh last April.

"I can't believe she's buying that big-ass cake with food stamps," the woman said, according to Riley.

Riley, 19, had just used a government-issued debit card to pay for most of her groceries, which included a cake for her son that said "Happy First Birthday Xavier" in a theme from the movie "Cars." She glared at the women for a second, then decided to confront her.

"I was just like, 'Shut the fuck up,'" Riley said. "You don't know what I'm doing with these food stamps."

But many Americans do not want to let people on food stamps eat cake. This sentiment is particularly prevalent among conservatives in Congress. Cash register resentment of the sort directed at Riley feeds Republican animus toward the Supplemental Nutrition Assistance Program.

It's a petty path toward a huge target: As SNAP enrollment has surged to nearly 50 million in the wake of the Great Recession, the program's annual cost has more than doubled to $80 billion. Republicans want to shrink those numbers, but they missed their best chance in June, when a trillion-dollar farm bill failed in the House of Representatives, after the GOP sought deeper cuts than Democrats would accept.

Following the vote, Rep. Louie Gohmert (R-Texas) got to work telling a familiar story, one he said he'd heard many times from broken-hearted and angry constituents. Its protagonist is a hardworking Texan waiting in line at the grocery store. Someone's buying Alaskan king crab legs in front of him, and he's looking at them longingly, dreaming of the day he can afford such a luxury. Then the person buying them whips out his EBT -- an Electronic Benefits Transfer card for food stamps.

"He looks at the king crab legs and looks at his ground meat and realizes," Gohmert said, "because he does pay income tax ... he is actually helping pay for the king crab legs when he can't pay for them for himself."

And that's how cash register resentment becomes crabby conservatism -- the belief that your own struggles are tangled up in another person's safety net.

RIB-EYE STEAKS AND WINE

Janina Riley said the situation at Giant Eagle didn't escalate after she confronted the mumbling woman. She figured it wouldn't have started at all if the person had known that she was studying to become a nurse, and that she already worked more than 30 hours a week as an aide in a nursing home.

People have to be poor in order to receive nutrition assistance. The maximum gross monthly income for SNAP eligibility in Pennsylvania , for instance, is $2,018 for a household of two, and the family can't own assets worth more than $5,500 (though there are several exceptions, like a single car). Most recipients qualify based on their participation in another means-tested program like Medicaid.

At $10 per hour, Riley's wages leave her poor enough to qualify for $124 a month in food stamps. At the Giant Eagle that day, she used her full monthly benefit to pay for part of her cart full of food and roughly $80 of her own money for the rest.

"Most people do work. It's just we don't make enough money, that's the problem," Riley said. "The biggest misconception is that people on food stamps sit on their butts all day."

She's part of the 30 percent of SNAP recipients who earn money by working, and the 91 percent whose annual incomes are at or below the poverty line. Most recipients are either children, elderly or disabled.

But in the public imagination, hard-working single moms rent a room with king crab welfare queens.

It's a gripe going back at least 20 years. In 1993, the Columbus Dispatch ran a letter to the editor lamenting a food stamp recipient buying "two bottles of wine, steak and a large bag of king crab legs.''

The crab complaint has recurred more than a dozen times in newspapers around the country, including this 2007 missive from a reader in the Myrtle Beach Sun-News: "After working a typical 12-hour shift, I had to stop by the local grocery store. Standing in line behind an oversized woman with three kids, I noticed the items going through the checkout. She had two 10-pound packs of frozen crab legs and two large packs of rib-eye steaks among a couple of vegetable items totaling up to an excess of $60."

Nutrition assistance is a federal program administered by states at the ground level. State and federal lawmakers have long sought new restrictions on what nutrition assistance can buy. Fancy food stories are often the reason. For instance, Wisconsin state Rep. Dean Kaufert (R-Neenah) cited cash register situations as his rationale for a bill restricting food stamp purchases earlier this year.

"Anecdotally, weve all heard the stories about people standing in line behind the person who is buying the tenderloin, the porterhouse and theyre using their EBT card to do it, while you and I who are getting by, were buying ground beef," Kaufert told a local radio station. "Thats a small share of those folks. But also Ive been at the convenience store many times -- the amount of nachos and soda thats being purchased by kids with their parents EBT card, I think its time to say no to that."

In June, New York Mayor Michael Bloomberg led a coalition of big-city mayors asking Congress to restrict food stamps from paying for soda in the name of fighting obesity.

Junk food and crab legs aren't even the worst of it. "Every day we hear of reports of food stamps being used to pay for beer, cigarettes, cell phone bills, and even cars," Sen. Dan Coats (R-Ind.) said on the U.S. Senate floor in February. "That hardly needs to be mentioned because it is something we have come to understand -- there is a lot of misuse of tax dollars."

Elizabeth Lower-Basch, an analyst for the Center for Law and Social Policy, noted the secondhand nature of many of the anecdotes.

"It's definitely a meme. You hear it a lot," Lower-Basch said. "There's a lot of a-friend-told-me-she-saw type stories. I'm not going to tell you there aren't cases of people making lousy choices, but they are far more visible in the public imagination."

'PLAIN-OUT HATEFUL'

Federal law says food stamps can't be used to buy booze, cigarettes, vitamins, or household supplies. But they can buy almost anything else at a supermarket, so long as it isn't served hot for immediate consumption. So what do people buy with SNAP?

A government survey from the late-'90s found that meats accounted for 34.9 percent of food stamp purchases, grains 19.7 percent, fruits and veggies 19.6 percent, and dairy products 12.5 percent. Soft drinks made up 5.6 percent and sweets 2.5 percent.

If the government decides to restrict purchases to "wholesome" food, it won't be easy.

"No clear standards exist for defining individual foods as 'healthy' or 'unhealthy,' and federal dietary guidance focuses on an overall dietary pattern -- that is, a total diet approach -- that promotes moderation and consumption of a variety of foods without singling out individual foods as 'good' or 'bad,'" the Food Research and Action Center said in a January report.

"Consider the following examples: some candy bars have fewer calories from fat than a serving of cheddar cheese, and soft drinks have less fat and sodium per serving than some granola bars," the report continued. "If the focus for restrictions was foods high in fat and sodium, would candy bars and soft drinks be eligible but cheddar cheese and some granola bars ineligible?"

But not even avoiding the most obvious junk food or extravagances will spare an EBT card carrier from cash register resentment.

"You can't win," Lower-Basch said. "When someone's going to think you've got too much sugar, someone else is going to think you've got too much fat. Part of the reason we don't have restrictions is you could never get everyone to agree."

While Janina Riley's birthday cake irked one fellow customer, Patrick McCallister's vegetables annoyed another. McCallister said that in 2003 and 2004, he had fallen on hard times after a divorce and used nutrition assistance to feed his three kids.

"Especially because my family was on food stamps, I felt like that was a taxpayer-supported program aimed at helping my children do as well as they could in life," McCallister said. "I focused on buying fresh fruits, vegetables, whole-grain bread."

McCallister, now 46 and living in Stuart, Fla., had been standing at the Publix supermarket register for several minutes as the cashier sorted through his month's worth of food and his coupons when the confrontation happened.

"This woman comes up behind me," he said. "The food is all tallied up, I pull out the food stamp card, which is very difficult to disguise. In Florida at the time it was a big American flag. The woman remarked, 'I wish I could eat so well. Maybe I should go on food stamps so I could eat that well."

McCallister, who no longer receives assistance and now works as a reporter for a local newspaper, said he explained he'd taken care to buy good food since he was using taxpayer funds. The lady seemed annoyed by both the quality and perhaps also the quantity of McCallister's food. He said he turned his back as she insulted him.

"I felt disappointed in the human race," McCallister said. "I was never happy using food stamps. I don't believe anybody who's shopping with food stamps takes any kind of thrill in standing at the register and pulling out that distinguishable card."

Food stamp recipients who've experienced cash register resentment often say their antagonists have insufficient information to judge fairly.

Last fall, Cynthia Nerger of Warner Robbins, Ga., had a dispute with a manager at a Kroger grocery store over whether SNAP covered an item in her cart. After she prevailed in the argument, the manager delivered a low blow: "Excuse me for working for a living and not relying on food stamps!" Nerger burst into tears.

What the manager didn't know is that Nerger couldn't work because she'd been waiting for a kidney transplant and had to spend 12 hours a day in dialysis. She took her case to a local TV station and soon won national attention . Kroger transferred the manager and offered Nerger a $15 gift card.

"All it is is people are just plain-out hateful," Nerger said.

FEELING POOR

Actual food stamp fraud is a real thing. Since Carl Clark of Staten Island, N.Y., witnessed it firsthand, he thinks of it whenever he hears about nutrition assistance.

Clark, 48, said that roughly 10 years ago, he and his ex-wife would habitually take their EBT cards to willing supermarkets and have the cashier ring up $100 worth of fake purchases in exchange for $70 in cash, a payday for customer and cashier both. It's a classic example of SNAP trafficking, a type of fraud the Agriculture Department has long tracked.

Clark said he and his wife have since split up and he left that life long ago, but his impression of food stamps is permanently stained.

"Everyone I know who's been on food stamps have been involved in that scam," Clark said. After his divorce, he got a financial sector job, but lost it last year. Unemployed again, he said he may soon be eligible for nutrition assistance once again, but won't sign up. (Three out of 10 Americans eligible for the program aren't enrolled.)

"I'd rather go into a soup kitchen," Clark said.

Though Clark said he sees widespread wrongdoing, the government says SNAP fraud has declined dramatically. The trafficking rate is down from 4 cents per dollar of benefits in 1993 to 1 cent from 2006 to 2008, according to the department's latest data.

Buying fancy stuff with food stamps isn't fraud -- it's just something that seems unfair to people who think a government safety net should afford poor people modest food only. More broadly, the idea is that the poor should feel poor at all times until they're not poor anymore.

Not all poor people see things that way, though. Sara Woods of Knoxville, Tenn., is not ashamed to say she once bought crab legs with food stamps.

In December, she and her husband asked their six kids what they wanted for Christmas dinner. Woods said her husband's good in the kitchen, since he works as a cook in one restaurant and as a sous-chef in another. It was one of the only times he didn't have to work on Christmas Day, and he wanted to cook for his family. Their 15-year-old daughter wanted crab legs.

"Everybody could pick one thing, and that was the one thing she wanted," Woods said.

She didn't get any guff at the store, but she's familiar with register resentment from when she worked as a cashier in 2004 and 2005. It always came from a certain type of person -- a nosy type, she said.

"It would be somebody who was really watching every little thing the person was doing, every little thing they're putting in their cart," Woods said. "They were all up in their cart, all up in their business, they were like, 'Look how many kids, too many kids and now we have to support them.'"

As for why people make questionable purchases, Woods has a theory from her own experience.

"When you get that money, you feel like you can breathe," she said. "I can understand why people would buy things that people think are outrageous. When it comes, you feel like I can buy whatever food I want right now. You never can buy whatever you want. My clothes are hand-me-down, furniture second-hand. The food is new and mine."

Danielle Schlanger contributed to this story.

Correction: This article originally misidentified Sen. Dan Coats (R-Ind.) as a senator from Illinois.